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34 DERMATOLOGY DETAILS PEER REVIEWED collection tube with a small amount of sterile saline added. Do not use lidocaine if a culture is going to be obtained from the biopsy specimen. Lidocaine inhibits various gram-positive and gram- negative bacteria, mycobacteria, and fungi. 3 SAMPLE SUBMISSION Blot tissue samples to remove blood and immediately place the samples into the biopsy jar to avoid the desiccation that can rapidly ensue. Ten percent buffered formalin is the most commonly used fixative and must be used with a minimum of 10 parts formalin to 1 part tissue to ensure adequate fixation. Place elliptical or large punch specimens dermis side down on a piece of wooden tongue depressor or cardboard to prevent curling artifact, allow them to adhere for 30 to 60 seconds, and then place them upside down in the biopsy jar. Samples from different locations can be placed into different jars or may be marked with ink or suture to differentiate them if needed. This is important when removing multiple tumors or when multiple processes are suspected. Separate crusts may also be included in the biopsy jar wrapped in lens paper. Notify the pathologist that additional crusts have been submitted. If samples are mailed in the winter months, allow fixation for at least 12 hours before cold exposure. 1 Contact the laboratory to determine if further fixation or additives are required. Send samples to a veterinary pathologist specializing in dermatology or a veterinary dermatologist with expertise in dermatopathology. Ask your local dermatologist whom they would recommend in your area. Make sure to provide signalment, comprehensive history (including previous medications), examination findings, and differentials. Always include a lesion description and location on the animal. Good-quality pictures can be helpful as well. NEXT STEPS A biopsy is merely part of a clinical workup and may not give a definitive diagnosis. However, even without a definitive diagnosis, some of the differential diagnoses may be eliminated or the results may establish a group of diseases to consider (eg, hormonal or allergic disorders). This information must then be combined with the patient's history, clinical signs, and possibly additional testing to establish the diagnosis. If the description provided by the dermatopathologist does not correlate with the clinical appearance of the lesions, consider that the clinical interpretation has been incorrect or that the biopsy specimens are not representative of the disease. 4 Some cases will require repeat biopsy procedures because diagnostic lesions may not be present at the initial biopsy. References 1. Miller WH, Griffin CE, Campbell KL. Diagnostic methods. In Muller & Kirk's Small Animal Derma tology, 7th ed. St. L ouis: Elsevier, 2013, pp 92-95. 2. Henfrey JI, Thoday KL, Head KW. A comparison of three local anaesthetic techniques for skin biopsy in dogs. Vet Dermatol 1991; 2(1):21. 3. Williams BJ, Hanke CW, Bartlett M. Antimicrobial effects of lidocaine, bicarbonate, and epinephrine. J Am Acad Dermatol 1997; 37(4):662. 4. Shearer D. Dermatopathology. In Foster AP, Foil CS (eds): BSAVA Manual of Small Animal Dermatology, 2nd ed. Gloucester: BSAVA, 2003, pp 31-36. FIGURE 2. A punch biopsy sample is grasped by the subcutaneous tissue, making sure not to crush the sample. Sarah Bartlett Sarah Bartlett, DVM, MS, DACVD, graduated from the University of Florida College of Veterinary Medicine and completed an internship at Affiliated Veterinary Specialists in Maitland, Florida. She completed her dermatology residency at Animal Dermatology Clinic in Marietta, Georgia. She has recently returned to Animal Dermatology Clinic in Marietta after working in Florida for 2 years. She is a member of the ACVD Credentials Committee, and her clinical interests include allergic and immune-mediated skin disease.